School Receives Grant To Study Reducing Skin Cancer Risk From Arsenic In Water

Oct 01, 2005

Researchers at Columbia University's Mailman School of Public Health announced on Oct. 12 they have been awarded a $10 million grant from National Cancer Institute (NCI) to conduct a chemoprevention trial of 4,500 adults in Bangladesh who were exposed to very high levels of arsenic in drinking water. The research will focus on reducing the high rates of skin cancer and other cancers in this population, which are believed to be a result of arsenic exposure.

The Mailman School is combining its research efforts with the International Center for Diarrheal Disease Research, Bangladesh, Centre for Health and Population Research, an internationally renowned public health research institution based in Bangladesh, to investigate whether vitamin E and/or selenium has a beneficial effect in reducing skin and other cancers.

The study led by Habibul Ahsan, MD, MMedSc, associate professor and director of the Center for Genetics in Epidemiology in the Department of Epidemiology at the Mailman School of Public Health, also will be coordinated by the Herbert Irving Comprehensive Cancer Center (HICCC) at Columbia University Medical Center and NewYork-Presbyterian Hospital. The HICCC is one of only three NIH-designated Comprehensive Cancer Centers in New York state.

Skin cancer is the most common arsenic-related cancer. Nearly 100 million people in the world are chronically exposed to arsenic and, therefore, are at increased risk of skin and other arsenic-induced cancers. Arsenic has been shown to produce mutations in cancer causing genes, but it is also believed that antioxidants, such as vitamin E and selenium, may impede the carcinogenic effects.

"If the research confirms that supplementing one's diet with vitamin E and/or selenium, has an impact on changes of pre-malignant skin lesions and its progression to skin cancer, the results could provide essential data on potential low-cost interventions for reducing the cancer risk among millions of arsenic exposed population in Bangladesh as well as other parts of the world," said Ahsan, principal investigator of the study.

The most common route of human exposure to arsenic is through ingesting drinking water that is naturally enriched with arsenic. With an estimated 57 million people in Bangladesh having been exposed to high levels of arsenic from drinking water, starting in the 1970s, UNICEF and the Bangladeshi government installed a large number of hand-pumped tube-wells to provide pathogen-free drinking water to the population of Bangladesh.

"Over the past several years, nationwide surveys have established that half of Bangladesh's 10+ million tube wells serving 95 percent of the population have been contaminated," Ahsan said. "Given that tens of millions of people have already accrued decades of chronic exposure, an epidemic of arsenic-induced cancers is thus almost inevitable in the Bangladesh population."

Long-term studies from Taiwan indicate that once chronically exposed, a population continues to experience elevated cancer risk for several decades. With very little currently known regarding cancer prevention for the millions of arsenic-exposed individuals, particularly those who have already developed pre-malignant skin lesions, evaluation of appropriate preventive measures using a well-designed trial is urgently needed, according to the team of researchers.

The NCI grant includes funding for patient recruitment, questionnaire, clinical data assessment, and follow-up of 4,500 patients for the five-year intervention period. The study builds on some of the activities developed in coordination with the Superfund Basic Research Program, funded by the National Institute of Environmental Health Sciences (http://www-apps.niehs.nih.gov/sbrp). The work of the Superfund involves studies at four sites in the United States, and also focuses on carcinogenic, reproductive, and childhood effects of arsenic exposure in drinking water in Bangladesh.

As part of this large program project, Ahsan and his colleagues have been following nearly 12,000 men and women since 1999 in Bangladesh for another epidemiologic study to investigate health effects of arsenic and this newly-funded NCI grant will start a new dimension to the ongoing Columbia University research activities in Bangladesh.